MITRAL VALVE DISEASE is the most
serious problem facing the Cavaler King Charles Spaniel today. Nearly 100%
of all Cavaliers will develop MVD by age 10. MVD is a developmental fault
involving the mitral valve of the heart. With each beat of the heart the
four different valves open to let blood through at the right time and then close
so that blood cannot flow backward. When a dog develops MVD, the
collagen/connective tissue that makes up the mitral valve starts to break down
and starts causing the mitral valve to not be able to close all the way.
Blood leaks backwards and this *leakage* causes a sound that is called a murmur.
Over time the mitral valve gets sloppier and more and more blood leaks backwards
causing the murmur to get louder. The more blood that leaks backwards the
harder the heart has to work to keep the blood moving so the body can get enough
oxygen. The valve can get so sloppy that eventually the dog will go into
congestive heart failure. At this point in time, medication is necessary
to prolong the dog's life.

Following
are graphs showing the age of onset of first murmur that can be heard (the
beginning of MVD) and percentage of affected Cavaliers from the United States
and Great Britain. As you can see, there are no statistically significant
differences between these countries. This is to show you CLEARLY that
Cavaliers all over the world develop MVD at nearly the same ages and at nearly
the same rates. Don't be fooled by those who tell you "their"
line is free from MVD or "Irish, English or imported" Cavaliers are
healthier than those elsewhere. This is simply NOT true! You now
have proof--in the form of the graphs below--that MVD is just as prevalent in
Great Britain (which includes Ireland) as in the United States. Despite
MVD, the average lifespan is 10-11 years, and quite a few live 13-15 years.
However, a certain percentage will not make it much past 7 or 8 years of age.

Left/Top
Graph
Dr. Darke's early survey of heart murmurs in Cavaliers. The
prevalence increases with increasing age. Over 30% of dogs
2-4 years old, 50% at age 5-6, and all dogs 11 years and
older had heart murmurs.

Right/Bottom
Graph
Beardow and Buchanan's study. Age specific prevalence of left
apical systolic murmurs grades 1-6 in 394 Cavaliers. The numbers
above the columns represent the numbers of dogs in each group. The
percentage of murmur positive dogs increases with age.

Sweden
did a study in 1993, showing that MVD is a multi-factoral polygenic trait.
This means that genetic factors AND environmental factors (i.e. diet,
environmental toxins/vaccinations, fitness of body--underweight or overweight)
can contribute to how severely MVD will be expressed. The genetic
component is QUITE strong. Puppies WILL, on average, tend to follow in
their parent's footsteps as to when they will develop MVD, in fact this
incidence is somewhere in the 86-88% range in just the first generation.
This means that if both mom and dad are clear of MVD past age 5, about 86-88% of
their offspring will still be clear of MVD at approximately age 5 as well.
And this ALSO means that if both parents develop mitral valve disease BEFORE age
5, close to 86-88% of their offspring will ALSO develop MVD BEFORE age 5.
BUT, approximately 10-15% of their offspring will not follow in their parents
footsteps and may develop MVD earlier or later.

Below
is a graph showing the results of this study. The chart on the left
explains what intensity murmur each color represents. No murmur is what is
hoped for. The higher the grade, the worse the murmur. The chart on
the right shows the comparison of the mean parental grading. *Mean
parental grading* is the average of the murmurs of the two parents. If
both parents were grade 1, then the mean parental quality would be 1 + 1 divided
by 2 = 1. If one parent was a grade 1 and the other a grade 2 then 1 + 2
divided by 2 = 1.5. The graph clearly shows the parents that were most
affected (had a higher grade MVD murmur) produced more affected offspring (by
age 5) than did the parents less affected.

Due
to this evidence, the geneticists proposed a voluntary protocol which aims to
delay the onset of MVD in offspring. This protocol asks for breeders to
breed only:

~~~~~~~~

HEART
PROTOCOL

(1)
Individual Cavaliers that have attained the age of 5 and are SUBSEQUENTLY (AFTER
age 5) found
to still be clear of MVD (regardless of parental status);

OR

(2)
Cavaliers that have attained the age of 2.5 years and are subsequently found to
still be clear of MVD, AND whose parents BOTH attained the age of 5 years and
were subsequently found to be still clear of MVD;

AND

in
a way that puts emphasis on long-lived, delayed onset ancestors.

~~~~~~~~

This *cut-off point* of 5 years of age is only a first proposal. It is
hoped that as the incidence of early-onset MVD improves, the cut-off age of 5
will be changed.

The
cut-off age of 5 was chosen for two reasons: (1) Dogs that attain
the age of 5 still free of MVD are already in the upper 50th percentile--or are
in the *better half*, the half which we WANT to use in our breeding programs.
(2) Since the gene pool for the Cavalier is small, eliminating only the *worst*
half of the population will still allow us to maintain a decent-sized gene pool
and progress slowly towards a later and later onset of MVD.

Although
the protocol is voluntary, it is hoped that as time goes by, more and more
breeders will be able to follow this protocol.

BEFORE
you buy a puppy from ANY breeder, please ask for copies of the current cardiologist
heart clearances of BOTH parents. Because MVD is a developmental fault, it
simply canNOT be checked for in a puppy. It is the
parents that need the
clearance form. Look any forms you receive over well. Virtually all
of them, even if they vary from the examples shown, will state the name of the
dog that was examined, the date of examination somewhere on the form and clearly
state the name of the Board CERTIFIED veterinary cardiologist. Please look
for these specifics. A vet signed statement is
NOT acceptable. The vast majority of veterinarians CANNOT hear low grade
murmurs (grades 1 and 2), so ONLY Board Certified Cardiologist clearances are
acceptable.

For
more on MVD, please go to this site: www.ckcsc.org.
This is the Cavalier King Charles Spaniel Club, USA, Inc., site. Click on
Health and then MVD to read more. You can also view and/or download
the Transcript from the Atlanta Heart Symposium in 1998, which presented the
Swedish study and proposed the heart protocol, at the CKCSC site also.

On
cardiologist clearances it is important to note: (1) The name of the dog
listed on the certificate to be sure it matches the name of a parent of a
prospective puppy. (2) The date of the examination. (3) The date of
birth of the dog that was examined--please cross check the date of birth and the
date of examination to figure out the age of the dog at the time of the
examination. (4) The name of the cardiologist who did the examination.

The
following are some samples of acceptable cardiologist heart clearance forms.
Please click on the picture to see a larger version of the form.

Below is the OFA Application the Cardiologist fills out to send to the OFA for
certification.

Last is a copy of the *official* OFA cardiac clearance form which a breeder
receives after sending in the Application form. When looking at this form,
be sure to note whether or not there is a letter "C" right after the
last slash in the OFA Registration Number. The letter *C* indicates that
the heart auscultation was done by a board certified cardiologist. If
there is no *C*--the certificate is not acceptable.

NOTE
O.F.A. NUMBER
KCS-CA3874/25F/C-VPI is the number
25F is age in months/sex of dogC-means a cardiologist cleared the dog
PI-means the dog has Permanent Identification

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